OS: Linux Minut 18.3, Intellij "Community 2020.1 EAP"
I've just started using Intellij, after using Eclipse for many years.
I've naturally searched on this problem: the few relevant hits seem to date from years ago.
What happens: I right-click (this is another bugbear: I hate being obliged to use the mouse for ANYTHING, and Shift-F10 doesn't work): the context menu displays... I try to move the focus to something in the menu... and - woosh - the menu has gone.
Nor does it help to keep the right button depressed: the menu still disappears on "single items"... by that I mean menu items which are not followed by "...". With items which obviously lead on to another submenu the context menu does NOT disappear.
As suggested from my searching, I have tried tweaking the File --> Settings --> Keymap settings. But nothing has worked so far.
It's odd when you come across something like this: is no-one else experiencing the same problem?